Fuse



Patented Nov. 13, 1945 UNHTED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 7 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to fuses, and more particularly' to fuses for non-rotating projectiles such as mortar projectiles,

An object of this invention is to provide a fuse for mortar projectiles and the like which is of very simple construction permitting most of the parts thereof to be die-cast from plastic material. A further object of this invention is to provide in such a fuse a mechanism which renders it bore safe, i. e. incapable of being red until the projectile, of which it forms a part, has left the bore of the gun. Another object of the invention is to provide a fuse having a firing pin which actuates the fuse at substantially any angle of impact.

Other objects and advantages of the invention will appear in the following description of several embodiments thereof as shown in the accompanying drawing in which Figure 1 is a sectional view of a preferred embodiment,

Figure 2 is another view of the embodiment shown in Figure 1, partially in section and taken at right angles thereto, the parts shown in section being taken along the line 2--2 of Figure 1,

Figure 3 is a plan view of the slider shown in Figure 1,

Figure 4 is a sectional View of a modified form of firing pin and retaining means therefor assembled in the nose of a fuse, and

Figure 5 is a perspective view of the modification of Figure 4.

Referring now to Figures 1 and 2, a fuse body I, preferably die-cast from plastic material, is provided with a truncated conical nose portion 2 and. a cylindrical basal extension 3 which provides a booster cavity 4 containing a booster charge 5. The cylindrical extension 3 is provided with threads at 6 so that the fuse may be screwed in the nose of a projectile (not shown) as is conventional. The booster cavity is closed, after lling, by means of booster plug 'I screwed into the bottom opening of the cavity. The body is provided with a ash passage S containing an initiating charge 9 separated from the booster charge by a plug I0. A primer I I is contained in a cavity I2 in a slider I3, to be described more particularly hereinafter. The slider is mounted for movement transversely of the fuse body in a cylindrical way I4. As shown in Figure 1, the slider is positioned at the right-hand end of the way I 4, in which position the fuse is safe, the priming composition being out of alignment with the firing pin I5 and also out of alignment with the initiating charge 9. A slider spring I6, abutting against slider retaining screw I'I, urges the slider to the left, as shown in Figure 1. However, the slider is prevented from moving to the left to arm the fuse by the engagement of abutment IB against the stop and lock pin I3, which retains the slider in safe position.

The stop and lock pin is seated in recess 20 and yieldingly biased in a forward direction by stop and lock pin spring 2| working between a collar 22 on the pin and the stop and lock pin retaining screw 23. The pin is provided with a dependent projection 24 which, in striking against screw 23, prevents complete retraction of the pin within recess 20 but permits the free end of the pin to move below the level of surface 25 on the slider as it is set-back due to inertia when a projectile carrying the fuse is fired from a gun. An arming wire 26 is provided which must be removed before the fuse can be fired. This wire is inserted in a hole in the fuse body and passes through a hole 21 in the stop and lock pin, `effectively keeping the stop and lock pin in forward position to insure that the slider will not move to the left and thus prematurely arm the fuse.

The slider I3 is shown in vertical section in Figure 1 and in plan in Figure 3 preferably is machined from brass bar stock, and, as set forth above, is provided with an abutment I8. This abutment is complementary to the stop and lock pin I9 and, as shown, is semicylindrical. A hole 28 is drilled vertically through the slider, providing in its lower portion a recess in which the stop and lock pin engages when the slider has moved to final position bringing the priming charge in ring alignment with the firing pin. A slot 29 is provided in the bottom of the slider connecting the bottom of hole 23 with the cylindrical abutment I 8. This slot clears the stop and lock pin as the slider moves from right to left. The sides of cylindrical abutment I8, slot 29, and hole 28 each contact in turn the stop and lock pin thereby always preventing rotation of the slider in its way.

The top of hole 28 is routed for part of its depth at 30 to provide a recess, the top of which engages the shoulder at the base of the tapered portion of the firing pin to maintain the slider in an intermediate position while the fuse is being accelerated. The hole 28 is positioned to engage the stop and lock pin when the priming charge cavity is in alignment with the firing pin, and the routed portion 30 at the top of the slider is positioned to permit the surface 25 to engage the top f 32 of die-cast plastic material secured to a shank portion 33 of aluminum or brass. The firing pin is slidably mounted in cylinder 34 formed in the fuse body and is urged forwardly by spring 35. The pin is retained in its cylinder by firing pin retaining pin 36 xed in the fuse body and engaging recess 3l on the pin shank. The striker head of the pin is of mushroom shape so that the fuse will be actuated at near grazing angles of impact.

Operation-The fuse is attached to a suitable projectile and the arming wire 26 is removed. The fused projectile is then fired from the gun. During initial acceleration, the stop and lock pin and the firing pin are both set back relative to the fuse body, the stop and lock pin clearing the abutment on the slide and permitting the slide to move to the left under the inuence of the slider spring until the routed abutment 3l] engages the conical point of the firing pin, thus stopping the slider in an intermediate safe position. The slider remains in this intermediate safe position until the forces of acceleration have decreased to such an extent that the firing pin spring returns the ring pin to substantially normal position retracting the point of the pin from the routed recess 30. This occurs after the projectile has left the bore of the gun; thus the fuse is safe during its travel through the bore. The slider spring then moves the slider still further to the left to a position where the stop and lock pin engages in hole 28 locking the slider in nal position with the primer in firing alignment with the i'lring pin. Upon impact, the firing pin is forced back against the primer, detonating it. The flash from the primer ignites the initiating charge which, in turn, ignites the booster charge, which then res the main charge contained in the shell.

Figures 4 and 5 show an alternative form of ring, pin and means for retaining it in the fuse body. The ring pin 38 in this modification preferably is formed entirely of die-cast plastic material and is provided with a cored slot 39. A retaining pin 40, formed of spring steel or the like, passes through the slot in the pin, down the sides of the fuse body and its ends are engaged in holes 4 l drilled into the fuse body. The arms 42 of the retaining pin lie in slots 43 formed in the side of the body. This construction allows the pin to be easily assembled to the fuse body in the following manner: The firing pin and firing pin spring 44 are assembled and inserted in the cylindrical opening at the nose of the body. The retaining pin is passed through the slot 39, and its inturned ends engaged in the top of slots 43. y The retaining pin is forced downwardly, its ends riding in slots 43 until they reach holes 4 I, when the spring action of the retaining pin forces the ends thereof into the holes, thus locking the pin to the body. The slot 39 in the firing pin permits the necessary movement of the pin to take place while retaining the firing pin in the fuse body.

The striker head 45 of the firing pin shown in Figures 4 and 5 differs from that shown in Figures 1 and 2 in that the former is a straight sided head while the latter is a mushroom shaped head. 'I'he mushroom shape is desirable because it assures functioning of the fuse at near grazing angles of incidence while the straight sided head is advan- A more urgent use.

tageous in that there is no possibility of dirt or foreign matter becoming lodged under an overhanging part of the head.

The embodiments of the invention disclosed herein are not intended to limit the scope of the invention described in the appended claims. However, these embodiments are particularly adapted to be manufactured readily in large quantity from synthetic plastic materials and the like. Plastic die-castings may be used for nearly all the component parts of the fuse whereby equivalent quantities of more strategic materials, such as aluminum and brass, may be released for Also, die-casting of these parts releases critical machine tool hours for diversion to the production of more pressing items.

I claim:

1. A non-rotating type fuse comprising a body having a transverse slideway therein and a bore normal to and intersecting the slideway, a ring pin in the bore with spring means normally maintaining it above the slideway, said ring pin being arranged to be operated upon setback against the influence of said spring means, a slider mounted in the slideway and carrying a primer charge, spring means urging the slider into the slideway, and control means holding the slider in retracted, safe position before firing, said control means operating upon setback to release the slider, said iiring pin being operated upon setback to arrest the movement of the slider in an intermediate, safe position, and thereafter, when its setback urge ceases, to release the slider to permit the last mentioned spring means to move the slider to an armed position, said control means, after its setback urge has ceased, being movable to a position to lock the slider in its armed position and with the primer charge in line with the ring pin.

2. A non-rotating type fuse comprising a body having a transverse slideway therein and a bore normal to and intersecting the slideway, a spring backed firing pin in said bore with its striking end normally above the slideway, a slider in the slideway and carrying a primer charge and having a firing pin engaging abutment, spring means urging the slider into the slideway, control means having a portion normally in the slideway and engaging and holding the slider in retracted, safe position, and spring means urging said portion into the path of movement of the slider, said control means operable upon setback to release the slider, said firing pin being simultaneously operated by setback to engage said firing pin engaging abutment to arrest the movement of the slider in an intermediate, safe position, the ring pin being returned to its normal position, when its setback urge ceases, by its spring to permit the rst mentioned spring means to move the slider to a fully armed position and said control means being actuated by the last mentioned spring means to lock the slider in its last mentioned, iinal position. Y

3. A non-rotating type fuse comprising a body having a transverse slideway therein and a bore normal to and intersecting said slideway, a firing pin in said bore and a spring maintaining the firing pin above the slideway, said pin being operable upon setback to thrust its end into said slideway, a slider in said slideway and carrying a primer charge, spring means urging the slider into the slideway, said slider having a recess in its upper side normally in line with the firing pin, anda lower recess substantially in line with said pin, a spring urged rod extending into the slideway in engagement With the slider to primarily hold it in a normal, retracted and safe position, said rod operable upon setback to release the slider, the firing pin being simultaneously operable upon setback to enter the upper recess to arrest and hold the slider in an intermediate, safe position, said firing pin being thereafter operated by its spring to Withdraw the firing pin from engagement with the slider when the inertia of the firing pin ceases, to permit the slider to move by its spring to its nal, armed position, and said rod engaging the lower slider recess to arrest and lock the slider in final, armed position.

4. A non-rotating type fuse comprising a body having a transverse slideWay and a bore normal to and intersecting the slideway, a slider in the slideway and carryingV a primer charge, resilient means constantly urging the slider into the slide- Way, control means including a spring urged portion extending into the Slidevvay and normally locking the slider in initial unarmed position, said control means portion being operable by setback to release the slider and to subsequently engage it to arrest and lock the slider in final armed position after the setback urge on said portion has ceased, and a spring backed firing pin in said bore and operable by setback to project its end into the slideway into engagement with the slider to arrest it in an intermediate safe position, said pin releasing the slider when the setback urge on said pin has ceased, to permit the slider to be moved by the resilient means to its final, armed position, and to be again engaged by the control means portion, whereby the slider is arrested and locked in its nal armed position.

5. A non-rotating type fuse comprising a body having a transverse slideway therein and a longitudinal bore intersecting the slideway, a firing pin slidably engaging the bore, a spring normally holding the iiring pin out of the slideway, a slider mounted in the slideway and carrying a primer charge, said slider having an abutment to be engaged by the firing pin, a spring engaging the slider and urging it toward one end of the slide- Way to position the primer in alignment with the ring pin, and a spring urged stop extending into the slideway and engaging the slider to initially hold it in a retracted, disarmed position with the primer out of alignment with the firing pin, said stop being setback by inertia to release the slider to cause it to be projected by its spring, said ring pin being simultaneously setback to engage the abutment to arrest and hold the slider in an intermediate, disarmed position, and the springs of the ring pin and stop thereafter reacting to overcome the inertia created by the initial acceleration of the fuse to return the firing pin to a projected, cocked position thus releasing the slider so that its spring can move it to a fully projected, armed position, and the stop moving thereafter into engagement with the slider to lock it in its armed position.

6. A fuse as in claim 5, and means forming a part of said slider for engaging the stop to hold it in a retracted position, after the slider has moved from its retracted position and before it reaches its nal, armed position, to positively prevent the stop from arresting the movement of the slider to a fully armed position.

7. A fuse as in claim 5, said i'lring pin having an elongated opening, and a bail of spring wire extending therethrough and having its ends detachably anchored in the fuse body for limiting the sliding movement of the ring pin.

JOHN J. HORAN. 

